This project will use data from the Medical Expenditure Panel Survey (MEPS) to study how health care market structure and the structure of the safety net affects access to and utilization of medical care by uninsured persons. Specifically, the project will use the MEPS to examine the effects of health care market structure and the safety net on whether uninsured persons have a usual source of care and on multiple measures of utilization including physician visits, non-physician visits, hospital admissions and total hospital nights, home health care visits, use of the emergency room, use of preventative care, use of prescription medicines, and total medical care expenditures. The major methodological innovation in the project will be the use of highly detailed measures of the safety net that include the distance form individual uninsured persons to different types of safety net providers. In addition, the project will explore alternative approaches to modeling use in order to account for the dynamics in health insurance.